Methods and systems for reconstruction of low frequency particle velocity wavefields and deghosting of seismic streamer data
First Claim
1. A method to determine structural information about a subterranean formation to be carried out by a computer system that includes one or more processors and one or more data-storage devices, the method comprising:
- computing vertical velocity wavefields associated with marine seismic receivers based on reflectivity of a time-varying, rough free surface profile above the marine seismic receivers and for frequencies below a threshold frequency using pressure wavefields measured at the receivers;
computing receiver deghosted wavefields based on the measured pressure wavefields, vertical velocity wavefields measured at the receivers above the threshold frequency, and the computed vertical velocity wavefields; and
generating an image of the subterranean formation using at least in part the receiver deghosted wavefields, the image revealing structural information about the subterranean formation.
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Accused Products
Abstract
Computational methods and systems for deghosting marine seismic streamer data are described. In particular, an exploration-seismology vessel tows a number of streamers that form a data acquisition surface located beneath a free surface. The methods computationally deghost or substantially remove receiver ghost signals from seismic data recorded by steamer receivers. The deghosting methods include low frequency compensation to recover vertical velocity wavefield information that is typically lost due to a low signal-to-noise ratio over a low frequency range independent of the free surface conditions or the shape of the data acquisition surface.
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Citations
20 Claims
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1. A method to determine structural information about a subterranean formation to be carried out by a computer system that includes one or more processors and one or more data-storage devices, the method comprising:
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computing vertical velocity wavefields associated with marine seismic receivers based on reflectivity of a time-varying, rough free surface profile above the marine seismic receivers and for frequencies below a threshold frequency using pressure wavefields measured at the receivers; computing receiver deghosted wavefields based on the measured pressure wavefields, vertical velocity wavefields measured at the receivers above the threshold frequency, and the computed vertical velocity wavefields; and generating an image of the subterranean formation using at least in part the receiver deghosted wavefields, the image revealing structural information about the subterranean formation. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A computer system to determine structural information about a subterranean formation, the computer system comprising:
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one or more processors; one or more data-storage devices; and a deghosting routine stored in one or more of the one or more data-storage devices and executed by the one or more processors, the routine directed to retrieving from the one or more data-storage devices pressure wavefield data measured at marine seismic receivers over a frequency range and vertical velocity wavefields measured at the receivers above a threshold frequency of the frequency range; computing vertical velocity wavefields associated with marine seismic receivers for frequencies below the threshold frequency using the measured pressure wavefields and reflectivity of a time-varying rough free surface profile above the marine streamer; computing receiver deghosted wavefields over the frequency range based on the measured pressure wavefields, the measured vertical velocity wavefields above the threshold frequency, and the computed vertical velocity wavefields; and generating an image of the subterranean formation using at least in part the receiver deghosted wavefields, the image revealing structural information about the subterranean formation. - View Dependent Claims (9, 10, 11, 12, 13, 14)
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15. A non-transitory computer-readable medium having machine-readable instructions encoded thereon for enabling one or more processors of a computer system to perform the operations of
computing vertical velocity wavefields associated with marine seismic receivers for frequencies below a threshold frequency using pressure wavefields measured at the receivers and reflectivity of a time-varying rough free surface profile above the marine streamer; -
computing receiver deghosted wavefields based on the measured pressure wavefields, vertical velocity wavefields measured at the receivers above the threshold frequency, and the computed vertical velocity wavefields; and generating an image of the subterranean formation using at least in part the receiver deghosted wavefields, the image revealing structural information about the subterranean formation. - View Dependent Claims (16, 17, 18, 19, 20)
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Specification